Scabies: causes, symptoms, diagnosis, treatment

Prurigo is a heterogeneous disease characterized by rashes of intensely itchy pruriginous elements, which are papules of a dense consistency, hemispherical or conical in shape, often with a vesicle on the surface, located on an edematous (urticaria-like) base.

Causes of pruritus. Caused by many exogenous and endogenous factors (food allergens, medications, insect bites, etc.), observed in many diseases of internal organs (liver disease, leukemia, lymphogranulomatosis and other malignant processes) and the central nervous system.

Symptoms of prurigo. It occurs in attacks, in most cases acutely or subacutely (infantile prurigo, acute prurigo of adults by Besnier, etc.), and there are also chronic forms (prurigo of Hebra, prurigo of Dubreuil). It most often develops in childhood (strophulus), but is also observed in adults as a newly developed process, as well as one that has persisted since childhood with temporary improvements and exacerbations. Nodular prurigo has slightly different clinical manifestations, characterized by the presence on the skin mainly of the lower extremities of large hemispherical papules of a pale pink color, dense consistency, covered with hemorrhagic crusts. often with hyperkeratosis. The rashes exist for a long time, are resistant to treatment, hyperpigmentation remains in their place, as well as scars due to deep scratching. Manifestations characteristic of nodular prurigo are observed in the chronic form of phlebotoderma, which develops at the site of mosquito bites.

Prurigo pigmentosa is described, developing mainly in the spring and summer, predominantly in women, probably from friction with underwear on the body, in the form of itchy red papules, sometimes arranged in a network. After their regression, spotted or network pigmentation remains.

Pathomorphology of pruritus. In the acute form of the disease in children (infantile pruritus), the histological picture resembles that of limited neurodermatitis, acanthosis and hyperkeratosis are expressed, with vesiculation, bubbles and cortical elements are found in the upper parts of the epidermis. The inflammatory reaction in the dermis is small.

In acute pruritus in adults, acanthosis and spongiosis are observed in the area of the element with the formation of vesicles in the upper parts of the Malpighian layer of the epidermis, more often under the stratum corneum. In the upper third of the dermis, there are perivascular infiltrates of lymphocytes with an admixture of neutrophilic and eosinophilic granulocytes.

In the chronic form, fresh papules show moderate acanthosis, spongiosis with the formation of small vesicles, and parakeratosis. In the upper part of the dermis, there is a moderately expressed lymphocytic infiltrate, located mainly perivascularly. Papules with excoriation on the surface of the epidermis are covered with crusts containing disintegrated nuclei of infiltrate cells. With regeneration phenomena, pseudo-epitheliomatous hyperplasia with unevenly expressed epidermal outgrowths may develop in the epidermis. In such cases, the inflammatory infiltrate is expressed significantly in the dermis.

In nodular prurigo, pronounced acanthosis and hyperkeratosis are observed, sometimes papillomatosis with uneven proliferation of epidermal growths. Hyperplasia of cutaneous nerves and neurolemmocytes, as well as fibrosis of the dermis can often be observed. Electron microscopy reveals proliferation of axons and neurolemmocytes, dystrophic changes in nerve structures in the form of swelling of the axon. The disease is differentiated from keratoacanthoma and other diseases accompanied by pseudoepitheliomatous hyperplasia. It should be noted that the histological picture may be indistinguishable from changes in atopic dermatitis and limited neurodermatitis. In such cases, the correct diagnosis is made based on clinical data.

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ]